To Seal Or Not To Seal

Marble and granite are natural geological formations formed many millions of years ago. Every slab of stone is unique and unlike any other in the world, and is what makes natural stone so beautiful. The individuality of each stone slab is what lures so many homeowners and businesses to choose natural stone for their projects.
The individuality of each stone slab means that no two slabs will have the same absorbent qualities. If all stone came from one quarry, they would be similar, but still unique. For example, Black Galaxy from Brazil may be less absorbent than a similar Absolute Black from India, which is more absorbent. It does not matter where the stone in your project is being used, be it a kitchen or bathroom, if it is a natural stone, it will need to be sealed.

All granite, marble and limestone must be sealed. Impregnating sealers like Miracle 511 or Miracle Porous Plus are the best choices. Miracle Porous Plus is formulated for the softer sedimentary stones, such as limestone and marble, which are more porous. Miracle 511 is formulated for harder igneous stones, like granite and quartzite.

A frequently asked question is how often stone needs to be resealed. Our experience at Northbay Stone Works (NBSW) is that using the correct sealer, when applied properly, can last for years before resealing is necessary. The myth of resealing every six months is not true, unless you are using a water-based sealer. NBSW is a firm believer in solvent based sealers: every natural stone that we fabricate in our shop is sealed before it arrives at your project for installation. NBSW recommends resealing when your stone is no longer repelling water or oil. When you see the stone getting darker in color, it’s time to think about another coat of sealer.

NBSW often receive calls about water rings and spots (stains) on their marble or limestone surface. These are not stains – they are etches or corrosion caused by the chemical reaction between the calcium in the stone and the acid in the product(s) that come in contact with it. Products with acid in them can range from citrus fruits, soda, tomatoes or any low pH products. Placing any of these types of products on the marble or limestone can cause a noticeable etch. The only way to fix these marks is to professionally re-polish or re-hone the stone surface.